In general, a rotating electrical machine comprises a casing having inside a stator, rigidly connected to the casing, and a rotor, for example with permanent magnets, rotatably connected to it.
An electronic module or electronic control module, connected to the stator, comprises a plurality of active and passive electronic components forming a power section, and a plurality of electronic signal components, forming a control section.
The electrical machines referred to in this description are of the closed type, in particular the so-called “sealed” type, that is, sealed electrical machines, and having the relative electronic control module inside. The casing and a cap form a closed container from which protrude connection terminals provided for the power supply of the control electronics.
A prior art rotating electrical machine equipped inside with an electronic control module is described in application WO2009/066248 the name of the same Applicant.
In that solution, the electronic module comprises a plurality of copper conductor tracks on which the electronic power components are mounted and a printed circuit on which only signal components are mounted, welded to the conductor tracks.
The conductor tracks are “embedded” in a supporting element made of plastic material by overmolding.
The electronic module is cooled by placing in contact the conductor tracks with a dissipating element formed by the cap of the motor, using “pads” with high thermal conductivity.
A limit of reliability of the solution is due to the possibility of occurrence, in the presence of more or less sudden temperature variations, of breakages of the welds between the printed circuit and the conductor tracks on account of the difference between the thermal expansion coefficients of the printed circuit and of the plastic material in which the above-mentioned conductor tracks are “embedded”.
Another prior art solution is schematically shown in FIG. 1 and relates to a rotating electrical machine 100 comprising an electronic circuit 101 having all the power components 102 positioned on the same side of the printed circuit 103. Some tracks of the printed circuit 103 implement the direct connections between the power components 102. In this case, the heat generated by the power components 102 is dissipated by placing in contact with a dissipator 104 the side of the printed circuit opposite the one on which the power components 102 are located, by interposing an electrical insulating layer 105.
This solution also presents a limit in terms of reliability since the heat generated by the power components 102 flowing through the printed circuit 103 may adversely affect the condition of both the printed circuit and the connections of the power components 102.